Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

Small pieces of calcium carbonate react with dilute hydrochloric acid: $2\text{HCl(aq)} + \text{CaCO}_3\text{(s)} \rightarrow \text{CaCl}_2\text{(aq)} + \text{H}_2\text{O(l)} + \text{CO}_2\text{(g)}$
(a)[1]

State what the state symbol (aq) means.

(b(i))[1]

Deduce the mass of calcium carbonate two minutes after the reaction starts.

(b(ii))[1]

Explain how the graph indicates that the calcium carbonate is in excess.

(b(iii))[2]

The experiment is repeated at a higher temperature, with every other condition unchanged. Draw a line on Fig. 6.1 to show how the mass of calcium carbonate changes at the higher temperature as time increases.

(c(i))[1]

Describe the effect, if any, on the rate of reaction when large pieces of calcium carbonate replace small pieces of calcium carbonate.

(c(ii))[1]

As the concentration of dilute hydrochloric acid rises, the rate of reaction of dilute hydrochloric acid with calcium carbonate rises too. Choose the correct unit of concentration: $\text{dm}^3/\text{g}$, $\text{g}/\text{dm}^3$, $\text{mol}/\text{dm}$, $\text{mol}/\text{dm}^3$.

(d)[3]

Explain these results by reference to kinetic particle theory.

(e)[1]

Hydrogen chloride decomposes to form hydrogen and chlorine at $1500^\circ\text{C}$. The reaction is endothermic. State what the term endothermic means.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: dissolved in water / aqueous

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